Much of today's unrecovered oil is in the form of viscous, low gravity crude oil found in shallow, low temperature reservoirs. These deposits of viscous oil are the target of substantial enhanced oil recovery efforts in the industry. Most of these reservoirs contain very high saturations of viscous oil in a loosely consolidated or unconsolidated sandstone or siltstone matrix. A successful means of recovering this viscous oil is to thin the oil thermally (steam or combustion) and produce the thinned oil to the surface. During production, substantial quantities of formation fluids and formation fines are produced to the surface, suspended in the crude oil. The produced fluid is then treated to separate the oil, water and solids.
The produced oil is then sold and the water is injected into water disposal wells, leaving the fines and formation sand. These fines and formation sands have been disposed of by injecting or pumping them into a formation. One such method for disposal of produced formation fines obtained during oil recovering is disclosed in U.S. Pat. No. 4,787,452 which issued to Jennings, Jr. on Nov. 28, 1988. Another method for recovering viscous oil by removing fines therefrom is discussed in U.S. Pat. No. 4,828,030 which issued to Jennings, Jr. on May 9, 1989. The produced fines were mixed into a desired hydraulic fracturing fluid which fluid is then used to fracture the formation. Once the formation has been treated, additional fines in slurry form are pumped into the formation. It has been determined that considerable unrecovered oil remains on the formation fines which are pumped into the formation.
Many industrial processes such as mining and oil recovery operations involve the treatment or handling of a solid which contains an oil. The solid may comprise fines suspended sand particles with globules of oil entrained thereon. Often, the oil is substantially removed prior to subsequent use or disposal of the fines. One method for removing oil from the fines is to use expensive surface treatment and separation methods. For example, oil is often removed from the fines in large settling basins. This treatment is generally ineffective for removing finely suspended oil on the sand particles. They are also very time consuming and costly.
Therefore, what is needed is a method to recover residual oil from fines or formation solids after placement of these fines or solids into a formation so as to facilitate the removal of oil therefrom.